On Sun, Jan 30, 2005 at 04:26:29PM -0500, Rick Apichairuk wrote: > Is the shared_buffers per process? The reason I ask is the formula > given on http://www.postgresql.org/docs/7.4/static/kernel-resources.html > for calculating how much SHMMAX you need is: > > SHMMAX = 250 kB + 8.2 kB * shared_buffers + 14.2 kB * max_connections > up to infinity No, it is system-wide. shared_buffers is used for a number of things, but any excess is used by PostgreSQL to buffer data it reads. Before 8.0 the consensus was that (unlike most databases) it's better to let the OS cache the data instead of PostgreSQL. 8.0 has a much more advanced cache management algorithm, so it might now be better to let PostgreSQL be your primary cache, but AFAIK no testing has been done to show that's the case. -- Jim C. Nasby, Database Consultant decibel@xxxxxxxxxxx Give your computer some brain candy! www.distributed.net Team #1828 Windows: "Where do you want to go today?" Linux: "Where do you want to go tomorrow?" FreeBSD: "Are you guys coming, or what?" ---------------------------(end of broadcast)--------------------------- TIP 7: don't forget to increase your free space map settings
